Sanding apparatus



Jan. 28, 1969 H. L. WARD SANDING APPARATUS Filed June 10, 1965 Sheet of C5 58 IE'LtEr-i /7@ INVESTOR. Huaeer L WAe J f .L E-E @w/ ah Jan. 28, 1969 H. WARD 3,423,881

SANDING APPARATUS Filed June 10, 1965 Sheet 3 015 56 IFLL E5.Z

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92 INVENTOR.

Jan. 28, 1969 H. L. WARD 3,423,881

SANDING APPARATUS Sheet Filed June 10, 1965 f LEE-4:

Fizz-E United States Patent 24 Claims ABSTRACT OF THE DISCLOSURE An abrading apparatus including a framework, pairs of feed rollers mounted on the framework, pairs of sanding rollers mounted on the framework for receiving a panel from the feed rollers and for abrading the opposite sides of the panel, and chain drive structure for driving the rollers in each pair of feed rollers in opposite directions, and for driving the rollers in each pair of sanding rollers independently of each other and in a direction tending to move toward the feed rollers, a panel passed between, and in contact with, the sanding rollers. For the purpose of adjusting the spacing between the rollers in each pair of rollers, vertically extending support rods are secured to opposite sides of the framework and bearing blocks are slidably mounted on each of said support rods and journal the opposite ends of the rollers. Structure is provided for independently adjusting the vertical position of each of the bearing blocks on its respective support rod.

This invention relates to an abrading or sanding apparatus used to polish by abrasion the surfaces of doors and similar large, flat, wooden or plastic panels. More particularly, but not by way of limitation, the present invention includes a sanding machine for sanding simultaneously the opposed surfaces of a large flat panel, with the machine being adjustable so as to permit panels of varying thicknesses to be passed therethrough, and the opposite sides of such panels quickly and smoothly finished by a sanding operation.

In the finishing of large panels, such as doors, cabinet panels and the like, a completely automatic machine which is capable of simultaneously sanding the opposed surfaces of the panel in an even expeditious manner has not been heretofore developed. In most instances where a fine finish is required, hand sanding is still frequently carried out, and even in automatic machines which accomplish the sanding, on one side of such panels, the machines are not readily adjustable to accommodate panels of differing thicknesses.

The present invention comprises an improved sanding or abrading machine which can be used to automatically feed and sand or abrade the opposed or reverse surfaces of large fiat panels of varying thicknesses. Replacement of the sanding surfaces used in the machine can be easily and quickly accomplished by reason of the quick detachable mounting of the sanding rollers therein, and the machine can be accurately and expeditiously adjusted to permit panels of varying thicknesses to be fed therethrough. The machine further can be easily operated to individually sand either of the opposed surfaces of the panel, or both surfaces concurrently.

Broadly described, the sanding apparatus of the present invention comprises at least one pair of opposed feed rollers spaced from each other to permit a panel which is to be sanded to be moved therebetween in contact with both of the feed rollers; a pair of opposed sanding rollers spaced from a common plane containing the axes of rotation of the feed rollers, and spaced from each other to permit a portion of a panel passing between the feed rollers to be simultaneously passed between the sanding rollers in contact with both of the sanding rollers; means 3,423,881 Patented Jan. 28, I969 for driving the two rollers in the pair of feed rollers in opposite directions of rotation from each other so as to move the panel toward the sanding rollers; means for independently driving each of the rollers in the pair of sanding rollers in opposite directions of rotation from each other, and in directions such that the sanding rollers, in their rotational movement, tend to move a panel being passed therethrough toward the feed rollers; and means for adjusting the spacing from each other of the rollers in each pair of rollers whereby panels of varying thicknesses may be passed through said sanding apparatus. In a preferred embodiment of the invention, a plurality of pairs of the feed rollers and sanding rollers are employed and are positioned relative to each other to sequentially engage a panel to be sanded as it is moved through the apparatus, thus permitting larger panels to be passed through the apparatus, and also permitting the pairs of sanding rollers to be spaced from each other along the path of movement of the panel to be sanded, and various types of abrading surfaces to be located on the several pairs of sanding rollers so as to accomplish a sequential degree of abrasion on the surfaces being finished, such as proceeding from an initial rough abrasion to a final, very fine, highly polished finish.

In a preferred embodiment of the invention incorporating a novel adjustable bearing structure for use in regulating or adjusting the spacing between the pairs of rollers which have been generally described as being included in the apparatus, the rollers are each mounted upon an elongated shaft with each shaft having each of its ends journa'led in a bearing block which is slidably supported on a stationary rod. These rods extend through a suitable draw plate or angle iron structure located at one end thereof, and the draw plate or angle iron structure further carries an adjusting shaft extending parallel to the rod and rigidly secured at one end to the bearing block. The end of the adjusting shaft which passes through the draw plate is peripherally threaded, and a pair of nuts are provided on opposite sides of the draw plate in threaded engagement with the adjusting shaft so that by manipulation of the nuts, the adjusting shaft may be made to move with respect to the draw plate, thus varying the distance between the bearing block and the draw plate and causing the bearing block to move along the length of the stationary rod. The bearing blocks which receive each of the ends of the shafts which support the rollers are similarly mounted for independent adjustment so that the spacing between the rollers can be varied as may be required in order to accommodate panels of varying thicknesses. It should also be pointed out that the adjustability of the bearing blocks and the several rollers which are supported thereby permit the rollers to be aligned as may be desired with a horizontally extending feed table so that a large panel may be moved evenly from the feed table onto the lower roller of the initial pair of feed rollers, and may be supported by the feed rollers without becoming misaligned with respect to the plane of the upper surface of the feed table.

From the foregoing description of the invention, it will have become apparent that it is a major object of the present invention to provide an improved sanding machine which can be utilized to sand one or both of the opposed monoplanar surfaces of a flat panel structure, such as a door or the like.

An additional object of the present invention is to provide a sanding machine incorporating feed rollers and sanding rollers which cooperate in the sanding of doors, cabinet panels and the like, with the spacing between the several sets of rollers being adjustable to facilitate the sanding of doors or panels of varying thicknesses.

An additional object of the present invention is to provide a sanding apparatus incorporating a plurality of independently driven sanding rollers which can be operated at varying speeds, and which can be utilized to sand or abrade either one or both of the opposed surfaces of a large flat panel.

Another object of the present invention is to provide a sanding machine incorporating a plurality of pairs of feed rollers and sanding rollers, with the sanding rollers being mounted to facilitate quick dismantling of the apparatus so as to permit access to be had to each of the sanding rollers when it is necessary to replace the abradin g or sanding material carried thereby.

Another object of the present invention is to provide a sanding machine which is mechanically sturdy and durable in construction, and which is characterized by a long and trouble-free operating life.

In addition to the foregoing described objects and advantages of the invention, additional objects will become apparent as the following detailed description of the invention is read in conjunction with the accompanying drawings which illustrate the invention.

In the drawings:

FIGURE 1 is a side elevation view of one embodiment of the sanding machine of the present invention illustrating a drive system utilized to drive the lower rollers in a plurality of sets of feed rollers utilized in the apparatus, and the drive system utilized to drive the lower rollers in a plurality of sets of sanding rollers utilized in the invention.

FIGURE 2 is a view in elevation of the opposite side of the sanding apparatus from that which is shown in FIGURE 1 and illustrating the drive system which is utilized to drive the upper rollers in the plurality of sets of feed rollers utilized in the apparatus of the invention, and further showing the drive system which is utilized to drive the upper rollers in the pairs of sanding rollers utilized in the invention.

FIGURE 3 is a view in elevation of the sanding apparatus of the invention as it appears when viewed from the end of the apparatus at which doors or other relatively large flat panel structures are introduced to the apparatus.

FIGURE 4 is a sectional view of the sanding apparatus of the invention taken along line 44 of FIGURE 1.

FIGURE 5 is a sectional view taken approximately long line 55 of FIGURE 3, but showing only the portion of sanding machine adjacent the discharge end thereof where the feed roller drive motor is located.

FIGURE 6 is a diagrammatic illustration of the manner in which the several pairs of feed and sanding rollers utilized in the invention are arranged relative to each other, and further depicting the direction of rotation of these rollers.

FIGURE 7 is a detail view illustrating in elevation the manner in which the rollers utilized in the invention are adjustably mounted in bearing blocks to facilitate a rapid and accurate adjustment of the spacing between the rollers in each pair of rollers.

FIGURE 8 is an end view of the structure shown in FIGURE 7, as this structure appears when it is rotated through 90' from the position which it occupies in FIG- URE 7.

In discussing in detail the various structural elements of the sanding apparatus of the invention, and the relationship which these elements bear to each other, the several main sub-combinations or sub-assemblies will be separately described, and then the overall operation of the machine will be discussed.

Framework and superstructm-e Referring to the drawings in detail, and particularly to FIGURE 1, the sanding apparatus of the present invention is supported by a framework 10 which includes vertical support members or legs 12 interconnected by a longitudinal brace 14 and a horizontal top supporting member 16. The legs 12 are also interconnected by a transversely extending brace 17 (see FIGURE 3) and a transverse top supporting member 18. Supported on the top of the horizontal supporting members 16 and secured thereto by any suitable means, such as by bolts 19 and stanchions 22, are a plurality of horizontally extending angle irons 26, with a pair of the horizontal angle irons extending parallel to each other on opposite sides of the framework 10. The horizontally extending angle irons 26 are each welded to a pair of angle irons 28 and 30 extending over a substantial portion of the length of the angle irons 26, and oriented with their flanges extending from one leg of the angle irons 26 in opposite directions, as best illustrated in FIGURE 3. For purposes of reference and clarity in the discussion which follows, the angle iron 28 will be referred to as the out-turned rod supporting angle iron, and the angle iron 30 will be referred to as the in-turned feed table supporting angle iron.

Secured at their lower ends to, and extending upwardly from, the out-turned angle irons 28 are a plurality. of support rods 32 which are spaced along the length of the out-turned angle iron, as best illustrated in FIGURES 1 and 2, which are views of the sanding machine as it appears when viewed from opposite sides thereof. Each of the support rods 32 has secured to the upper end thereof, an angle iron draw plate 34 which extends at a right angle to the axis of the respective support rod 32 and projects on each side of the axis of the support rod, as best illustrated in FIGURES 3 and 7. The angle iron draw plates 34 are each secured to the top of their respective support rods 32 by a horizontally extending flange 34a. Each of the draw plates 34 also includes an upwardly extending flange 34b which is welded or bolted to an upright member 36. The upper ends of the upright members 36 terminate in a common plane and are secured to a longitudinally extending angle iron blower support rail which extends substantially parallel to the horizontal top supporting member 16, and to the angle irons 26, 28 and 30.

A turnbuckle bracing element 40 is connected to each of the ends of each blower support rail 38 and extends downwardly therefrom to the respective out-turned angle iron 28 on the same side of the sanding apparatus as the respective blower support rail 38 is located. The blower support rails 38 preferably each comprises an angle iron having an in-turned horizontally extending flange 42 to which the turnbuckle braces 40 are connected, and which function to support a blower hood (not shown) over the portion of the sanding apparatus in which the sanding is accomplished.

At the end of the sanding apparatus into which a door or panel 45 to be sanded is introduced (the left side in FIGURE 1), a feed table plate 44 is supported in vertically spaced relation to the in-turned feed table supporting angle irons 30 by a plurality of vertically extending bars 46. The feed table plate 44 is a large board or metal plate of relatively great surface area which functions to support the door or panel 45 immediately prior to its being passed between the sanding rollers by the feed rollers, as hereinafter described. Supported beneath the feed table plate 44 by attachment to the lower surface thereof are a pair of switch boXes 48 and 50 which are controls for driving either the upper sanding rollers, or the lower sandmg rollers, or both sets of sanding rollers, for the purpose of sanding either the upper or the lower surface of a door or panel, or both, as hereinafter described in greater detail.

At the discharge end of the framework (the right side in FIGURE 1 and the left side in FIGURE 2), a panel discharge supporting plate 52 is provided in substantially coplanar alignment with the feed table plate 44. The panel discharge support plate 52 is supported upon the in-turned angle irons 30 and in vertically spaced relation thereto by a plurality of vertically extending bars 54. The panel discharge support plate 52, like the feed table plate 44, is a large board or metal plate of large surface area capable of supporting a door discharged from the apparatus.

Roller and bearing structure Having described the important elements of the framework and superstructure of the sanding machine of the invention, the discussion will next be directed to the manner in which a plurality of pairs of feed rollers and sanding rollers are mounted on the superstructure supported by the framework in adjustable bearings. Referring initially to FIGURE 6 of the drawings, it will be perceived that, in the illustrated embodiment of the invention, the sets of rollers which are provided include five sets of relatively small rollers keyed to shafts for rotation and operated by turning the two rollers in each set of the rollers in opposite directions to each other. These sets of small rollers are designated by reference characters 60a, 60b; 62a, 62b; 64a, 64b; 66a, 66b; and 68a, 68b. The postscript, a, of the character designation indicates that the roller is an upper roller in the roller pair, and the postscript, [1, indicates the roller is a lower roller in a roller pair. The arrow adjacent each of the rollers indicates the direction in which it is rotated during operation of the sanding machine. It will be noted that the two rollers in each pair of rollers are aligned with their rotational axes in a common vertical plane.

In addition to the five sets of feed rollers, two sets of sanding rollers designated 70a, 70b; and 72a, 72b, respectively, are located on opposite sides of the feed rollers 64a and 64b. It will be noted by referring to the direction of the arrows adjacent the sanding rollers that their direction of rotation during operation of the sanding machine is opposite that of the smaller feed rollers. It should be pointed out at this point, that though the directions of rotation during operation of the machine for each of the sanding rollers is illustrated in FIGURE 6 by arrows adjacent the rollers, both the rollers in each set of sanding rollers need not necessarily be utilized during the operation of the machine in that the machine permits either the upper or the lower surface of the door or panel 45, or both of these surfaces, to be sanded simultaneously.

The feed table 44 is schematically illustrated in FIG- URE 6 as being positioned to the right of the several pairs of feed and sanding rollers, and the discharge panel support plate 52 is positioned to the left.

The actual positions and appearance of the uppermost rollers in the several pairs of feed and sanding rollers can best be perceived by referring to FIGURE 4 of the drawings. It will be noted in referring to this figure that the rollers occupy the same relative positions as those illustrated schematically in FIGURE 6, and that the uppermost rollers of the several sets or pairs of rollers are spaced horizontally from each other along the superstructure of the machine and over the framework and the main angle irons 26 carried thereby. For convenient reference, the shafts upon which each of the several rollers are mounted for rotation therewith have been designated by the odd numbered reference numeral nearest the number carried by the respective roller, followed by the corresponding postscript of the roller, i.e., the shaft to which the upper sanding roller 70a is keyed has been designated as 71a, and the shaft to which the upper feed roller 60a is keyed has been designated 61a.

For the purpose of rotatably journaling the shafts upon which the several feed and sanding rollers are mounted, novel bearing block assemblies are provided for receiving the free ends of each of the shafts. The bearing block assemblies each include a pass through or open bearing block designated generally by reference character 80 and slidably mounted upon the respective support rod 32 (see FIGURE 7). The open bearing block 80 is so termed since the end portion of the shaft which it rotatably receives is permitted to pass all the way through the bearing which journals the shaft, and to project beyond the bearing block.

Each open bearing block includes a support rod engaging portion 82, and a journal carrying portion 84. The journal carrying portion 84 is provided with an open hearing or journal 86 mounted centrally in the journal carrying portion 84, and permitting the end of one of the roller shafts to be extended therethrough, as best illustrated in FIGURE 7. The support rod engaging portion 82 of the open bearing block 80 is provided with a set screw 88 which can be used to fix the position of the support rod engaging portion 82 on its respective support rod 32, as hereinafter explained. Self-tapping screws 90 are utilized for securing the journal carrying portion 84 to the support rod engaging portion 82 so that the two elements extend at right angles to each other, as will be apparent in referring to FIGURES 7 and 8, and can be quickly and easily detached from each other.

An adjusting shaft 92 is secured to the top of the support rod engaging portion 82 of the open bearing block 80 and extends vertically therefrom and passes through an aperture formed in the horizontally extending flange portion of the angle iron draw plate 34. The upper end portion of the adjusting shaft 92 is peripherally threaded and a pair of adjusting nuts 94 and 96 are threaded onto the peripherally threaded end portion of the adjusting shaft 92, and positioned on opposite sides of the horizontally extending flange portion 34a of the angle iron draw plate 34. This construction of the adjusting shaft 92 permits the vertical position of the open bearing block 80 on the support rod 32 to be adjusted so as to regulate and control the spacing between adjacent pairs of rollers, as will be hereinafter explained in greater detail.

Disposed on the opposite side of the sanding machine from that side at which the open bearing block 80 is located, and aligned therewith to receive the opposite end of the shaft which is passed through the open bearing block 80 is a closed bearing block designated generally by reference character 100. The closed bearing block 100 is constructed substantially identically to the open bearing block 80, except that the journal or bearing provided in the journal carrying portion thereof is closed so that the end of the shaft which it receives cannot be passed therethrough. Accordingly, all parts and elements of the closed bearing block 100 which correspond identically to parts of the open bearing block 80 have been identified by identical reference numerals. The closed bearing or journal in the journal carrying portion 84 of the closed bearing block 100, being closed rather than open, has been designated by reference character 102 (see FIGURE 8).

As in the case of the support rod engaging portion 82 utilized in the open bearing block 80, an adjusting shaft 92 is extended upwardly from the support rod engaging portion 82 of the closed bearing block 100, and is adjustably positioned relative to the horizontally extending flange 34a of its respective angle iron draw plate 34 by a pair of adjusting nuts 94 and 96. In summary then, the upper roller in each pair of rollers is mounted on the superstructure of the sanding apparatus by extending the ends of the shaft which carries the roller through a pair of bearing blocks which are slidably disposed on the support rods 32 at opposite sides of the sanding machine, and in horizontal alignment with each other. The two bearing blocks 80 and 100 which are used to receive opposite ends of the roller shaft differ in that one of the open bearing block 80 includes a journal carrying portion 84 which permits the end of the shaft to be completely passed therethrough to receive a drive sprocket, as hereinafter described, while the closed bearing block 100 located on the opposite side of the machine, and receiving the other end of the roller shaft, includes a journal carrying portion 84 having a closed journal or hearing to receive the other end of the shaft.

Each lower roller which is paired with one of the upper rollers mounted in the way which has been described immediately above is mounted on a shaft which passes through an open bearing block 80, and a closed bearing block 100 as shown in FIGURE 7 of the drawings. The open bearing block 80 and closed bearing block 100 which rotatably receive the ends of the shaft which carry the lower roller are, of course, disposed below the open bearing block 80 and closed bearing block 100 which carry the upper roller on the support rods 32. It will be noted in referring to FIGURE 7 that the arrangement of the two rollers and the respective bearing blocks is such that the open bearing block 80 of the lower roller is disposed at the opposite side of the sanding machine from the side upon which the open bearing block 80 utilized to support one end of the shaft of the upper roller is located.

Secured to the top of the support rod engaging portion 84 of the closed bearing block 100 which supports one end of the shaft of the lower roller is an adjusting shaft 106. The upper end of the adjusting shaft 106 is peripherally threaded and passed through an aperture in the horizontally extending flange portion 34a of the angle iron draw plate 34, and carries a pair of adjusting nuts 108 and 110. Similarly, a vertically extending adjusting shaft 112 is secured to the top of the support rod engaging portion 82 of the open bearing block 80 disposed at the other end of the lower roller and has its upper end adjustably secured to the angle iron draw plate 34 by a pair of adjusting nuts 114 and 116. It is to be noted at this point that the construction of all of the open bearing blocks 80 is identical, whether such bearing blocks be used to support one end of the shaft upon which an upper roller is mounted, or be used to support an end of the shaft upon which a lower roller is mounted. The same identity of construction is true of all of the closed bearing blocks 100. It is further reiterated at this point that the support rod engaging portions 82 of each of the open and closed bearing blocks 80 and 100 are secured to the journal carrying portion 84 of the bearing blocks by self tapping screws which permit the journal carrying portion to be quickly and easily detached from the support rod engaging portion. The purpose of this quick detachable arrangement will be hereinafter described in greater detail.

Power transmission system For the purpose of driving the lower rollers 70b and 72b in the pair of sanding rollers in rotation, a suitable motor 120 is disposed on a pedestal 122 extending from, and preferably partially or entirely supported by, the framework 10. The motor 120 is drivingly connected by a chain 124 to a sprocket 126 which is keyed to a shaft 128 for rotation therewith. The shaft 128 is rotatably journaled in a bearing block 130 which is supported by a suitable brace 132 extending outwardly from the framework 10, as best illustrated in FIGURES l and 3. The opposite end of the shaft 128 from that which is journaled in the bearing block 130 is rotatably journaled in a bearing carried by the horizontal top supporting member 16 of the framework.

In addition to the sprocket 126, the shaft 128 is also keyed to a sprocket 134 which engages a chain 136 which passes upwardly and around a pair of sanding roller sprockets 138 and 140 which are keyed to the projecting ends of the shafts 71b and 73b, respectively, these shafts being the shafts which carry the lower sanding rollers 70b and 72b, respectively. It will be noted in referring to FIGURE 4 that the shafts 71b and 73b carrying the lower sanding rollers 70b and 72b, respectively, are passed through the open bearing blocks 80 disposed on the left side of the sanding machine as it is viewed in plan in FIGURE 4 of the drawings and as it is seen in elevation of FIGURE 1 of the drawings.

For the purpose of maintaining a desired amount of tension in the chain 136, an adjustable idler sprocket 142 is positioned for engagement with the chain and is rotatably journaled in a plate 144 which is adjustably mounted for longitudinal movement on a supporting rod 146 extending upwardly from the pedestal 122. Adjustment of the position of the plate 144 on the supporting rod 146 is achieved by utilizing a pair of adjusting nuts 148 threaded on the end of the adjusting rod 146 and positioned on opposite sides of a flange carried by the plate 144. It will be apparent from the foregoing description and by reference to FIGURES l and 3 of the drawings that the tension in the chain 136 is adjusted by altering the axial position of the plate 144 carrying the sprocket 142 on the supporting rod 146.

The drive system for driving the upper rollers in each pair of sanding rollers idependently of the lower rollers is mounted to the right side of the framework 10 as it is viewed in plan in FIGURE 4 of the drawings. This side of the sanding apparatus is also illustrated in elevation in FIGURE 2. In refer-ring to these figures, it will be noted that a motor 150 is supported on a pedestal 152 which extends outwardly from, and is partially supported by, a framework 10. The motor 150 has a shaft extending outwardly therefrom which carries a sprocket 154. The sprocket 154 engages a chain which extends around a second sprocket 156 mounted on a shaft 158 which is rotatably journaled in a bearing block 160. The bearing block 160 is supported on a platform 162 extending laterally from the horizontal top supporting member 16 of the framework 10.

The shaft 158 also is provided with a second sprocket 164 (see FIGURE 3) positioned inboard on the framework 10 from the sprocket 156. The second sprocket 164 engages a drive chain 166 which extends upwardly around a pair of large sprockets 168, 170 which are keyed to the shafts 71a and 73a, respectively, which rotatably support the upper sanding rollers 70a and 72a, respectively. It will be noted in referring to FIGURES 2 and 7 that the drive chain 166 functions to drive the rollers 70a and 72a in the same direction (counterclockwise as viewed in FIGURE 2), which direction is counter to the direction of movement of the workpiece 45 through the sanding machine. It will be noted briefly at this point, and discussed in greater detail hereinafter, that the switch boxes 48 and 50 are utilized for controlling the motors 150 and 120, respectively, so that these motors may be independently energized and either the upper rollers 70a and 72a in the two sets of sanding rollers driven, or the lower rollers 70b and 72b driven, or both rollers in each pair of sanding rollers driven simultaneously.

The drive system which is utilized for driving the feed rollers in the desired direction of rotation has portions positioned on both sides of the framework 10 and can best be fully understood by referring to FIGURES 14. The motor which is utilized to provide the power for driving the feed rollers is indicated by reference numeral 174 and is shown as resting on the floor or other surface supporting the framework 10. It should be pointed out, however, that the motor 174 can suitably be positioned on the framework and such mounting constitutes the preferred arrangement where the sanding apparatus is to be transported from one location to another at some time during its operating life.

The motor 174 has a projecting shaft which has keyed thereto a pulley 176 (see FIGURE 3), and the pulley 176 carries an endless belt 178 best illustrated in FIG- URE l. The endless belt 178 is extended around a pulley 180 mounted on a shaft 182 which extends through a journal supported by, and extending upwardly from, the longitudinal brace member 16 of the framework 10. The shaft 182 also carries a second pulley 184 which is disposed inside the framework 10 as best illustrated in FIG- URE 5. An endless belt 186 connects the pulley 184 with a larger pulley 188 keyed to a shaft 190 which is journaled in a bearing block 192 mounted on the longitudinal brace 14 of the framework 10. The shaft 190 carries a small pulley 194 at its end disposed on the opposite side of the longitudinal brace 14 from the pulley 188,

9 and the pulley 194 is interconnected to a pulley 196 by an endless belt 198.

The pulley 196 is keyed to a shaft 200 which is journaled on the framework 10 and also rotatably carries a sprocket 202, as shown in FIGURE 1. A chain 204 is extended from the sprocket 202 over a large sprocket 206 which is keyed to the shaft 61b which is keyed to and rotatably supports the lower feed roller 60b in the initial pair of feed roller 60a and 60b. The arrangement of the roller 60b and its shaft 61b can be best perceived by referring to FIGURES 1 and 4. It will be noted that the shaft 61b extends through one of the open bearing blocks 80 and that the sprocket 206 is keyed to the shaft on the opposite side of the open bearing block 80 from the roller 60b. Engaging the chain 204 at a point intermediate the sprockets 202 and 206 which it engages is an idler sprocket 208 which is mounted on the framework 10 and is vertically adjustable thereon. Thus, the idler sprocket 208 can be utilized for adjusting the tension in the chain 204.

The remaining lower feed rollers 62b, 64b, 66b, and 68b disposed in the several pairs of feed rollers are driven by chain and sprocket drive linkages interconnecting them with the shaft 61b of the initial lower feed roller contacted by the workpiece 45 during its travel through the interconnected by a chain 214 to a sprocket 216 keyed to the shaft 63b on the lowermost roller in the second pair of feed rollers. The shaft 63b also carries a sprocket 218 which is connected by a chain 220 to a sprocket 222 keyed to the shaft 65b which rotatably supports the feed roller 64b. A second sprocket 224 carried by the shaft 65b is interconnected by a chain 228 to a sprocket 230 carried by the shaft 67b which supports feed roller 66b. Finally, an additional sprocket 232 carried by the shaft 67b is drivingly connected to a sprocket 236 on shaft 69b by a chain 234. It will be noted that all of the sprockets which have been described as carried by the shafts 61b-69b which rotatably support the lower feed rollers 6211-6821 are of equal size so that the feed rollers are driven at the same rate of speed and the workpiece 45 will be advanced at a substantially constant rate through the sanding apparatus.

In order to use the rotary motion imparted to the lower feed rollers 60b-68b in order to drive the upper feed rollers 60a-68a, the shaft 6% which carries the last lower feed roller 68b in the series is provided with a circular gear 240 which is disposed outboard on the shaft from the sprocket 236 and is, of course, keyed to the shaft for rotation therewith. The circular gear 240 meshes with a second circular gear 242 which is keyed to a shaft 244 journaled in a bearing block 246 supported on a platform 248 welded or otherwise suitably secured on the framework 10. Spaced inwardly from the circular gear 242 and also keyed to the shaft 244 for rotation therewith is a sprocket 250 which drives a chain 252 passing over a sprocket 254 keyed to the shaft 69a which supports the upper roller 68a in the last pair of feed rollers in the series. This arrangement can best be understood by referring to FIGURES l and 4 of the drawings.

By the described arrangement, the upper feed roller 68a is caused to rotate in the opposite direction from the lower feed roller 68b so that a workpiece 45 moving through the apparatus will be moved by the feed roller pair onto the panel discharge support plate 52. It will be noted that the manner of supporting the upper feed roller 6801 in its bearing blocks differs from the manner of support of any of the other rollers utilized in the apparatus in that a pair of open bearing blocks 80 are provided on opposite sides of the framework for receiving the opposite ends of the shaft 69a which carries the feed roller 68a,

rather than one closed bearing block and one open bearing block. The purpose of this arrangement is to permit the upper feed roller 68a to function as the kinematic chain or transmission inst-numentality translating the rotational movement from the lower rollers, as effected by the drive system indicated on the left-hand side of the apparatus as viewed in FIGURE 4, to the drive system utilized for driving the upper rollers as the same appears at the right-hand side of FIGURE 4.

The opposite end of the shaft 69a from that which carries the sprocket 254 thus passes through an open bearing block and is provided with a sprocket 260 which is keyed to the shaft for rotation therewith. The sprocket 260 drives a chain 262 which passes around a sprocket 264 keyed to the end of the shaft 67a which rotatably supports the upper feed roller 66a. A second sprocket 266 which is carried by the shaft 67a is drivingly interconnected by a chain 268 to a sprocket 270 carried by the shaft 65a. The shaft 65a also carries a second sprocket 272 which drives a sprocket 274 carried by the shaft 63a through a chain 276. The shaft 63a which carries the sprocket 274 also is keyed to a second sprocket 278 which is drivingly interconnected to a sprocket 2 80 carried on the shaft 61a by a suitable chain 282. In referring to the side of the machine illustrated in FIGURE 2, it will be noted that the sprockets which are keyed to the shafts 61a-69a which carry the upper feed rollers 60a6*8a are of substantially the same size, and that the manner in which the chains are used to interconnect the sprockets carried by these shafts is such that all of the upper feed rollers are driven in the same direction of rotation.

Operation In utilizing the sanding apparatus of the invention, a blower hood or other suitable blower or suction apparatus suitable for removing the fine wood dust created in large volumes during the sanding operation is initially mounted above the apparatus and may be conveniently supported on the blower support beams 38 which are carried at the upper ends of the upright members 36. The lower feed rollers 60b-68b are then aligned with each other and with the plane occupied by the top surfaces of the feed table plate 44 and the panel discharge support plate 52. Adjustment of the vertical position of the several lower feed rollers 60b68b is accomplished by loosening the adjusting nuts 108, 1 10, and 114, 116 which secure the adjusting shafts 106- and 112, respectively, in their positions relative to the respective draw plates 34. Thus, by screwing the adjusting nuts in one direction or the other on the peripherally threaded ends of the adjusting shafts 106 and 112, these shafts may be moved upwardly or downwardly through their respective apertures in the draw plates 34, and the positions of the several open blocks 80 and closed blocks on the support rods 32 thus adjusted. It may also be desirable to manipulate the set screws 88 which are passed through the support rod engaging portions 82 of the bearing blocks when the vertical adjustment of the rollers is accomplished, although the set screws '8-8 are provided primarily for the purpose of cfirmly scouring the feed and sanding rollers in a selected location for long periods of operation. Where adjustments are regularly made in the positions of the several rollers, the set screws '88 may be left in a loosened condition, or may be set up very lightly so as not to provide an unacceptable amount of frictional resistance to adjustment of the position of the rollers by the use of the adjusting shafts, and the respective adjusting nuts screwed on the adjusting shafts.

After the lower feed rollers 60b-6=8b have been adjusted so as to bring their upper peripheral surfaces into alignment along a common tangent which lies in the plane of the feed table plate 44 and the panel discharge support plate 52, the upper feed rollers 60a-6'8a are then similarly adjusted by use of the adjusting shafts 92 and the adjusting nuts 94, 96 to space them a distance above the lower feed rollers 60b-68b which will accommodate a workpiece of the thickness of the panel which is to be sanded. The spacing between each of the rollers in the several roller pairs will, of course, be identical and will preferably be such as to provide a relatively firm frictional engagement with the panel as it is passed between the feed rollers so that the panel may be kept moving through the apparatus without slippage.

Simultaneous with, or following, the adjustment of the feed rollers in their vertical positions on the framework, the sanding rollers 70a70b and 72a-72l2 may be similarly adjusted by the use of the adjusting shafts 92 used in conjunction with the bearing blocks which support the uppermost sanding rollers and the adjusting shafts 106, 112 'which are connected to the bearing blocks which support the lower sanding rollers. It is an important feature of this invention, and it should be carefully noted at this point, that each of the individual rollers used in the system, whether it be a feed roller or a sanding roller, can be individually adjusted in its vertical position in a rapid and effective manner, and that the several roller pairs in use are capable of accommodating and receiving panels which vary greatly in thickness and which are of substantially any length.

Once the rollers have been adjusted to the desired positions, the power transmission systems used in the apparatus are energized for driving some or all of the rollers in rotation. In the illustrated embodiment of the invention, all of the feed rollers 60a68a and 6012-681) are simultaneously driven in rotation, and the chain and sprocket drive system, which has hereinbefore been described, is effective to drive the upper feed rollers 6011-6811 in the opposite direction of rotation from the lower feed rollers 60b68b so as to cooperatively move a workpiece 45 through the apparatus. The speed of rotation of the feed rollers is relatively slow so as to permit the workpiece 45 to be thoroughly acted on by the sanding rollers as it passes therethrough. To this end, the system of belts and pulleys illustrated in FIGURE 1, and heretofore described, functions to substantially reduce the output speed of the average or ordinary electric motor 174 so that the feed rollers are rotated at a relatively slow speed. It will be apparent to those skilled in the art that the belt and pulley system employed could be simplified from that which is illustrated if a relatively low speed motor is available for use. It is desirable, however, to use at least one belt and pulley interconnection in the drive system for the feed rollers to allow for some slippage in the eventuality of the workpiece 45 encountering some obstruction in the sanding apparatus and being unable to move under the infiuence of the rotating feed thus be retarded in their rotational movement without stalling out the electric motor 174, or without the breaking of chains or other unyielding interconnecting driving means.

The reverse direction of rotation which must characterize the upper feed rollers 60a68a with respect to the lower feed rollers 60b-68b is accomplished through the medium of the meshing circular gears 240 and 242 and the manner in which these two gears are connected to the shafts 69b and 69a which carry the lower and upper feed rollers 68b and 68a, respectively.

In any given sanding or abrading operation, it may be desirable to finish by abrasion either the upper surface of the workpiece 45, the lower surface thereof, or both the upper and the lower surfaces. To this end, the apparatus of the invention is versatile and permits either the upper sanding rollers 70a and 72a in each pair of sanding rollers, or the lower sanding rollers 70b and 72b, or both the upper and lower sanding rollers in both pairs to be operated. For independent operation of the upper sanding rollers 70a and 72a, the motor 150 is energized, and through the described chain and sprocket linkages, drives the upper rollers 70a and 72a in rotation on their respective shafts 71a and 73a. The rollers are driven at the rollers. The feed rollers can 1?. same speed and in the same direction in the illustrated embodiment, although it is desirable in some instances to drive one roller at a greater or lesser speed than the other sanding roller.

As the workpiece is moved through the apparatus by the several feed rollers, it is contacted by the sanding rollers 70a and 72a which are rotated at a substantially higher speed than the feed rollers. It should be noted that at the time that the workpiece is contacted by the sanding rollers. It is still being biased forwardly through the sanding rollers by the feed rollers, and thus cannot be backed up in the machine by the reverse rotation of the sanding rollers. It is also generally true that the leading edge of the workpiece 45 will be engaged by the intermediate pair of feed rollers 64a and 64b as it continues to move through the leading pair of sanding rollers 70a and 70b so that even if the workpiece is out of engagement with the pair of feed rollers 62a and 621), it will still be gripped by rotating elements tending to move it toward the discharge end of the apparatus.

If it is desired to operate the lower sanding rollers 70b and 72b either independently of, or simultaneously with, the upper sanding rollers 70a and 72a, the motor 120 is energized using the switch and effectively drives the sprockets 138 and 140 carried by the shafts 71b and 73b, respectively, in rotation at substantially the same speed and in the same direction of rotation. With the described arrangement, it is thus possible to sand or finish either or both the upper and lower surfaces of the workpiece as it is moved through the apparatus.

It should be further pointed out that the types of abrading surfaces which are provided on the several sanding rollers may be varied in any desired manner, and it is possible to provide the sanding rollers a and 70b in the initial pair of sanding rollers with one type of abrading surface, for example, a course abrasive material, and the second pair of sanding rollers 72a and 72b with a relatively fine abrading material, to thereby provide the most efficient and effective type of sanding operation. On the other hand, the two lower sanding rollers 70b and 72b may be provided with an entirely different type of abrasive material from the upper rollers 70a and 72a so that the type of finish provided on the lower surface of the workpiece 45 differs from that which is provided on the upper surface.

As a final aspect of the invention which constitutes an important and useful feature thereof, the several rollers may be quickly and easily removed from the apparatus when it is desired to repair the removed roller, or a roller which is positioned below the removed roller, or where it is desired to remove the abrading or sanding surface on either the upper or lower sanding rollers. Removal of the rollers may be quickly accomplished by simply removing the self-tapping screws 90 which are provided in the bearing blocks and 100 for the purpose of holding the sup port rod engaging portions 82 thereof to the journal carrying portions 84. With the self-tapping screws removed, the journal carrying portions can be lifted upwardly on the ends of the respective shafts, and the rollers carried by the shafts can be bodily lifted out of the superstructure of the apparatus to expose the roller carried therebelow, and permit the surface of the lower rollers to be worked on or repaired. Replacement or repair of the removed roller is, of course, equally easily facilitated.

From the foregoing description of the invention, it will have become apparent that the present invention provides a novel, highly useful sanding apparatus which can be used to quickly finish in an effective and aesthetic manner, both the upper and lower surfaces of large fiat panels, such as doors and the like. Panels of varying thicknesses can be handled equally well by the apparatus, and the adjustments necessary to the rollers to accommodate panels of differing sizes can be quickly and easily effected. Maintenance of the apparatus is not difficult due to the accessible location of all sprockets and drive chains, and due to the ease with which the several rollers may be disconnected from their supporting structures and removed completely from the framework and the superstructure carried thereby.

Although a particular embodiment of the invention has been described herein in considerable detail, and several alterations to the illustrated structure have been suggested in the foregoing description, it is reasonable to expect that various departures and modifications can be made in the illustrated structure without departing from the basic principles which underlie the invention. All such modifications and innovations, therefore, which continue to utilize and depend upon the basic and fundamental principles herein enunciated, and upon which this invention is predicated, are deemed to be circumscribed by the spirit and scope of the invention except as the same may be necessarily limited by the appended claims or reasonable equivalents thereof.

I claim:

1. Apparatus for abrading comprising:

a framework;

at least one pair of feed rollers rotatably mounted on said framework and having their rotational axes aligned in a common plane, the feed rollers being spaced from each other to permit a panel to be sanded to be moved therebetween in contact with 'both of said rollers;

at least one pair of sanding rollers rotatably mounted on said framework and having their rotational axes aligned in a common plane extending parallel to the planes containing the rotational axes of said feed rollers, said sanding rollers being spaced from each other to permit a portion of the panel passing between at least one of the pairs of feed rollers to be simultaneously passed between one of the pairs of sanding rollers and in contact with both of the sanding rollers in said one pair;

means for driving the two rollers in each pair of feed rollers in opposite direction of rotation from each other to move said panel toward said sanding rollers;

means for driving at least one of the rollers in each pair of sanding rollers in rotation in a direction tending to move said panel toward said one pair of feed rollers;

support rods extending vertically from said framework at opposite ends of each of said pairs of rollers;

bearing blocks slida-bly mounted on each of said support rods and each rotatably journaling one of the rollers at one end thereof; and

means for independently adjusting the vertical position of each of said bearing blocks on its respective support rod.

2. Apparatus for abrading as claimed in claim 1 wherein said apparatus further includes:

a feed table plate supported on said framework and having an upper surface aligned with a plane extending between said roller pairs; and

a panel discharge support plate supported on said framework and positioned on the opposite side of said roller pairs from said feed table plate to receive a panel from said rollers after it has been abraded.

3. Apparatus for abrading as claimed in claim 1 and further characterized as including at least two pairs of feed rollers including pairs positioned on opposite sides of all the pairs of sanding rollers for feeding a panel to be abraded through the pairs of sanding rollers and out of said abrading apparatus after said panel has passed through said sanding rollers.

4. Apparatus for abrading as claimed in claim 3 wherein said apparatus includes five horizontally spaced pairs of feed rollers and two horizontally spaced pairs of sanding rollers, the sequence of occurrence of said roller pairs in a horizontal direction through the apparatus being two adjacent pairs of feed rollers, then a pair of sanding rollers, then a pair of feed rollers, then a pair of sanding rollers, then two adjacent pairs of feed rollers.

5. Apparatus for abrading as claimed in claim 1 and further characterized to include means for driving the other of the rollers in each pair of sanding rollers in rotation independently of said one roller in each pair of sanding rollers.

6. Apparatus for abrading as defined in claim 5 wherein said means for driving at least one of the rollers in each pair of sanding rollers comprises:

a motor;

a shaft driven by said motor;

a sprocket keyed to said shaft for rotation therewith;

a shaft rotatably supporting each of said one rollers in each pair of sanding rollers;

sprockets keyed to each of said roller supporting shafts for rotation therewith; and

a chain drivingly interconnecting said sprockets;

and wherein said means for driving the other of the rollers in each pair of sanding rollers in rotation independently of said one roller in each pair of sanding rollers comprises: a second motor; a second shaft driven by said second motor; a sprocket keyed to said second shaft for rotation therewith; other roller shafts rotatably supporting each of said other rollers in said sand roller pairs; sprockets keyed to each of said other roller shafts for rotation therewith; and a second chain drivingly interconnecting said other roller sprockets and said sprocket keyed to said second shaft. 7. Apparatus for abrading as claimed in claim 1 wherein said means for independently adjusting the vertical position of each of said bearing blocks comprises:

a draw plate secured to each of said support rods in a position above the bearing blocks carried thereby;

an adjusting rod secured to, and extending vertically from, each of said bearing blocks and passing through an aperture in said draw plate; and

retaining means on each of said adjusting rods axially movable on said adjusting rods and detachably engaging the respective draw plates for altering the relative positions of said adjusting rods to the respective draw plates through which they pass.

8. Sanding apparatus for finishing surfaces by abrasion comprismg:

a supporting framework;

a plurality of pairs of feed rollers rotatably mounted on said framework and each containing two rollers spaced from each other and adapted to frictionally engage a workpiece to be sanded and to advance said workpiece through said apparatus;

a pair of sanding rollers rotatably mounted in said framework and spaced from each other and from said pairs of feed rollers, said sanding rollers having their peripheral surfaces positioned on two parallel common tangents with the peripheral surfaces of the rollers in said pairs of feed rollers;

drive means for rotating each of the rollers in each pair of feed rollers in opposite directions to move the workpiece engaged by the feed rollers in each pair of feed rollers through the respective feed roller pair;

drive means for independently or simultaneously rotating each of the sanding rollers in said sanding roller pair in opposite directions from each other and in opposite directions from the direction of rotation of at least one feed roller having its periphery positioned on a common tangent with the respective sanding rollers in said sanding roller pair; and

means for independently adjusting the position of the axis of rotation of each of the rollers in each of said pairs of feed rollers and sanding rollers.

9. Sanding apparatus as claimed in claim 8 and further characterized to include shafts rotatably supporting each of said rollers, and wherein said adjusting means comprlses:

bearing means receiving the ends of each of said shaf t s;

and

means adjustably supporting each of said bearing means on said framework.

10. Sanding apparatus as claimed in claim 9 wherein said bearing means includes an open bearing block supported on one side of said framework and having an open bearing therein having one end of the respective shaft passed therethrough; and

a closed bearing block supported on the opposite side of said framework from said open bearing block and having a closed bearing therein receiving the opposite end of said respective shaft.

11. Sanding apparatus as claimed in claim 10 wherein said adjustable supporting means comprises:

a vertical support rod extending through each of said open and closed bearing blocks and secured at the lower end to said framework;

a draw plate mounted on each of said vertical support rods at a position above the respective bearing blocks mounted thereon;

adjusting shafts extending through said draw plates to each of said bearing blocks; and

means on said adjusting shafts detachably engaging said draw plates and selectively movable axially on said adjusting shafts.

12. Sanding apparatus as claimed in claim 9 wherein said first mentioned drive means comprises:

sprockets keyed to the shafts of each of said feed rollers;

chains interconnecting the sprockets of said feed rollers for driving the feed rollers in each pair thereof in opposite directions; and

a motor drivingly connected to one of said feed roller shafts.

13. Sanding apparatus as claimed in claim 12 and further characterized to include means drivingly interconnecting said motor with the shaft of said one feed roller, said interconnecting means comprising:

a shaft rotatably mounted on said framework;

a pulley and a sprocket mounted on said shaft for rotation therewith;

a driving sprocket mounted on the shaft of said one feed roller;

endless belt means drivingly interconnecting said motor with said pulley; and

a drive chain drivingly interconnecting the sprocket mounted on the shaft which is rotatably mounted on said framework with said driving sprocket.

14. Sanding apparatus as claimed in claim 13 and further characterized to include chain tensioning means mounted on said framework and cooperating with said drive chain for adjusting the tension therein.

15. Sanding apparatus as claimed in claim 11 wherein the portion of each of said adjusting shafts passing through the respective draw plate is peripherally threaded, and said means engaging said draw plate comprises a pair of adjusting nuts threaded on the peripherally threaded portion of each of said adjusting shafts and positioned on opposite sides of the respective draw plate.

16. Sanding apparatus as claimed in claim 11 and further characterized to include blower hood supporting means mounted on, and extending vertically upwardly from, said draw plates for supporting a blower hood over said framework and rollers.

17. Sanding apparatus as claimed in claim 9 wherein said means for independently or simultaneously rotating each of the sanding rollers in said sanding roller pairs in opposite directions from each other comprises:

a sprocket carried by the shafts rotatably supporting each of said sanding rollers;

a first motor mounted on said framework;

21. first chain drivingly interconnecting said first motor with those sprockets carried on the shafts of all of Cir said sanding rollers having their peripheral surfaces positioned on a common tangent extending between the two rollers in each pair of sanding rollers;

a second motor mounted on said framework;

a second chain drivingly interconnecting said second motor with those sprockets carried on the shafts of all of the sanding rollers not driven in rotation by said first motor and said first chain.

18. Sanding apparatus as claimed in claim 10 wherein said open and closed bearing blocks each include a journal carrying portion carrying the respective open or closed bearing; and

a second portion engaging said supporting means and quick detachably secured to said journal carrying portion whereby said rollers may be quickly and easily removed from said framework to permit the surfaces of the rollers to be renewed.

19. A machine for finishing a workpiece by abrasion comprising:

a supporting framework;

a plurality of pairs of feed rollers rotatably mounted on said framework for rotation about horizontal axes and spaced vertically from each other for engaging a workpiece to be advanced through said machine;

at least one pair of horizontally extending sanding rollers rotatably mounted on said framework and having at least one pair of said feed rollers mounted on opposite sides thereof for feeding a workpiece to said sanding rollers, and receiving said workpiece from said sanding rollers;

first driving means mounted on said framework and connected to at least one feed roller in each pair of feed rollers for driving said one feed roller in each pair of feed rollers in a common direction to advance a workpiece through said machine;

second driving means mounted on said framework and connected to one of the sanding rollers in each of the pairs of sanding rollers for driving said one sanding roller in the opposite direction of rotation from the direction of rotation of said one feed roller in each of said pairs of feed rollers;

third drive means mounted on said framework and operable independently of said second drive means for driving the second sanding roller in each pair of sanding rollers in a direction opposite the direction of rotation of said one sanding roller in each pair of sanding rollers;

shafts extending horizontally through, and keyed to,

each of said rollers;

vertically adjustable bearing means mounted on said framework and rotatably journaling the opposite ends of said shafts whereby each end of each of said rollers can be independently adjusted in a vertical direction.

20. A machine for sanding fiat panels comprising:

a horizontal framework having vertically extending supporting legs interconnected by two horizontal supporting means, said two horizontal supporting means extending parallel to each other on opposite sides of said framework;

a plurality of parallel, vertically extending supporting rods mounted on each of said horizontal supporting means and horizontally spaced therealong;

an open bearing block and a closed bearing block movably supported on each of said vertically extending supporting rods, each of said bearing blocks including a supporting rod engaging portion movably engaging said supporting rod, and a journal carrying portion projecting normal to said supporting rod engaging portion;

means quick detachably connecting said supporting rod engaging portions of said bearing blocks to the journal carrying portions thereof;

a horizontally extending draw plate mounted on each of said vertically extending supporting rods above said open and closed bearing blocks;

adjusting shafts interconnecting each of said bearing blocks with the respective draw plate located on the supporting rods carrying the respective bearing block;

means for changing the length of the portion of each of said adjusting shafts extending between said draw plates and said bearing blocks;

a pair of parallel, vertically aligned, horizontally extending feed roller shafts having their opposite end portions journaled in the bearing blocks movably supported on two of said supporting rods on opposite sides of said framework from each other, one of said feed roller shafts having an end portion projecting through the open bearing block disposed on one of said two supporting rods, and the other of said feed roller shafts having an end portion projecting through the open bearing block disposed on the other of said two supporting rods;

sprockets keyed to the projecting two end portions of each of said feed roller shafts for rotation therewith, said sprockets being disposed on opposite sides of said framework;

feed rollers mounted on each of said feed roller shafts;

a pair of parallel, vertically aligned, horizontally extending sanding roller shafts having their opposite end portions journaled in the bearing blocks movably supported on two others of said supporting rods on opposite sides of said framework from each other, one of said sanding roller shafts having an end portion projecting through the open bearing block disposed on one of said two other supporting rods, and the other of said sanding roller shafts having an end portion projecting through the open bearing block disposed on the other of said two other supporting rods;

sprockets keyed to the projecting end portions of each of said sanding roller shafts for rotation therewith, said sprockets being disposed on opposite sides of said framework;

sanding rollers mounted on each of said sanding roller shafts;

a first motor;

a speed reducer system interconnecting said first motor with said feed rollers, said speed reducer system including at least one pulley;

at least one belt interconnecting said pulleys with said motor;

a sprocket;

means drivingly interconnecting said pulleys with said sprocket; and

chain means drivingly interconnecting the sprocket in said speed reducer system with the sprockets on said feed roller shafts for driving said feed rollers in opposite directions from each other;

a second motor;

a chain drivingly interconnecting said second motor with the sprocket keyed to one of said sanding roller shafts;

a third motor; and

a chain drivingly interconnecting said third motor with the sprocket keyed to the other of said sanding roller shafts.

21. A machine as claimed in claim 20 wherein each of said adjusting shafts is extended through an aperture in the respective draw plate, and said means for changing the length of the portion of each of said adjusting shafts extending between said draw plate and said bearing blocks comprises a pair of adjusting nuts threaded on the peripherally threaded portion of said adjusting shafts and positioned on opposite sides of said draw plate.

22. A machine as claimed in claim 20 wherein said means quick detachably connecting said supporting rod engaging portion of said bearing blocks to the journal carrying portion of said bearing blocks comprises a plurali'ty of self-tapping screws extended through the supporting rod engaging portion into the journal carrying portion of each of said bearing blocks whereby the journal carrying portion of each of said bearing blocks can be quick detached from the supporting rod engaging portion thereof to permit the rollers utilized in said machine to be quickly removed and the surfaces thereof restored.

23. A machine as claimed in claim 20 wherein said machine includes a plurality of pairs of sanding rollers keyed to shafts mounted in bearing blocks on said vertically extending supporting rods in substantially the same manner as the sanding rollers described in claim 21.

24. A machine as claimed in claim 20 and further characterized to include means mounted at the upper ends of said supporting rods and above said draw plates for supporting blower apparatus.

References Cited UNITED STATES PATENTS 184,146 11/ 1876 Davies et al. 51-87 421,953 2/1890 Mattullath 51-87 782,798 2/1905 Rugg 51-87 3,166,874 1/1965 Bottcher 51-87 FOREIGN PATENTS 392,536 5/ 1933 Great Britain.

LESTER M. SWINGLE, Primary Examiner. 

